{"id":"CVE-2026-46250","summary":"MIPS: Work around LLVM bug when gp is used as global register variable","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nMIPS: Work around LLVM bug when gp is used as global register variable\n\nOn MIPS, __current_thread_info is defined as global register variable\nlocating in $gp, and is simply assigned with new address during kernel\nrelocation.\n\nThis however is broken with LLVM, which always restores $gp if it finds\n$gp is clobbered in any form, including when intentionally through a\nglobal register variable. This is against GCC's documentation[1], which\nrequires a callee-saved register used as global register variable not to\nbe restored if it's clobbered.\n\nAs a result, $gp will continue to point to the unrelocated kernel after\nthe epilog of relocate_kernel(), leading to an early crash in init_idle,\n\n[    0.000000] CPU 0 Unable to handle kernel paging request at virtual address 0000000000000000, epc == ffffffff81afada8, ra == ffffffff81afad90\n[    0.000000] Oops[#1]:\n[    0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Tainted: G        W           6.19.0-rc5-00262-gd3eeb99bbc99-dirty #188 VOLUNTARY\n[    0.000000] Tainted: [W]=WARN\n[    0.000000] Hardware name: loongson,loongson64v-4core-virtio\n[    0.000000] $ 0   : 0000000000000000 0000000000000000 0000000000000001 0000000000000000\n[    0.000000] $ 4   : ffffffff80b80ec0 ffffffff80b53d48 0000000000000000 00000000000f4240\n[    0.000000] $ 8   : 0000000000000100 ffffffff81d82f80 ffffffff81d82f80 0000000000000001\n[    0.000000] $12   : 0000000000000000 ffffffff81776f58 00000000000005da 0000000000000002\n[    0.000000] $16   : ffffffff80b80e40 0000000000000000 ffffffff80b81614 9800000005dfbe80\n[    0.000000] $20   : 00000000540000e0 ffffffff81980000 0000000000000000 ffffffff80f81c80\n[    0.000000] $24   : 0000000000000a26 ffffffff8114fb90\n[    0.000000] $28   : ffffffff80b50000 ffffffff80b53d40 0000000000000000 ffffffff81afad90\n[    0.000000] Hi    : 0000000000000000\n[    0.000000] Lo    : 0000000000000000\n[    0.000000] epc   : ffffffff81afada8 init_idle+0x130/0x270\n[    0.000000] ra    : ffffffff81afad90 init_idle+0x118/0x270\n[    0.000000] Status: 540000e2\tKX SX UX KERNEL EXL\n[    0.000000] Cause : 00000008 (ExcCode 02)\n[    0.000000] BadVA : 0000000000000000\n[    0.000000] PrId  : 00006305 (ICT Loongson-3)\n[    0.000000] Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000)\n[    0.000000] Stack : 9800000005dfbf00 ffffffff8178e950 0000000000000000 0000000000000000\n[    0.000000]         0000000000000000 ffffffff81970000 000000000000003f ffffffff810a6528\n[    0.000000]         0000000000000001 9800000005dfbe80 9800000005dfbf00 ffffffff81980000\n[    0.000000]         ffffffff810a6450 ffffffff81afb6c0 0000000000000000 ffffffff810a2258\n[    0.000000]         ffffffff81d82ec8 ffffffff8198d010 ffffffff81b67e80 ffffffff8197dd98\n[    0.000000]         ffffffff81d81c80 ffffffff81930000 0000000000000040 0000000000000000\n[    0.000000]         0000000000000000 0000000000000000 0000000000000000 0000000000000000\n[    0.000000]         0000000000000000 000000000000009e ffffffff9fc01000 0000000000000000\n[    0.000000]         0000000000000000 0000000000000000 0000000000000000 0000000000000000\n[    0.000000]         0000000000000000 ffffffff81ae86dc ffffffff81b3c741 0000000000000002\n[    0.000000]         ...\n[    0.000000] Call Trace:\n[    0.000000] [\u003cffffffff81afada8\u003e] init_idle+0x130/0x270\n[    0.000000] [\u003cffffffff81afb6c0\u003e] sched_init+0x5c8/0x6c0\n[    0.000000] [\u003cffffffff81ae86dc\u003e] start_kernel+0x27c/0x7a8\n\nThis bug has been reported to LLVM[2] and affects version from (at\nleast) 18 to 21. Let's work around this by using inline assembly to\nassign $gp before a fix is widely available.","modified":"2026-06-11T03:56:38.213803364Z","published":"2026-06-03T15:49:46.390Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46250.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/05bff9b0ae095b2420cfebb4a96759a09334bec6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1fe3b402b1e97a1718df3be0a1d3eee20133e735"},{"type":"WEB","url":"https://git.kernel.org/stable/c/30bfc2d6a1132a89a5f1c3b96c59cf3e4d076ea3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4dc65b40fb80c2020efbf139b9a38d30f9a37b92"},{"type":"WEB","url":"https://git.kernel.org/stable/c/561834f6d6f52b8a1791331e94b2aac753491d2a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9bc3b0ae5203aba650297fdf3e1e774125e423f2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c0155dee51b9f5f48aaf5c71cae005eb0e36521f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e3a6498a63394218561065a9a7a597a204f52f6a"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46250.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46250"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"279b991b24d2439fbe9d2f093988b9c8aed2603d"},{"fixed":"05bff9b0ae095b2420cfebb4a96759a09334bec6"},{"fixed":"1fe3b402b1e97a1718df3be0a1d3eee20133e735"},{"fixed":"4dc65b40fb80c2020efbf139b9a38d30f9a37b92"},{"fixed":"c0155dee51b9f5f48aaf5c71cae005eb0e36521f"},{"fixed":"e3a6498a63394218561065a9a7a597a204f52f6a"},{"fixed":"561834f6d6f52b8a1791331e94b2aac753491d2a"},{"fixed":"9bc3b0ae5203aba650297fdf3e1e774125e423f2"},{"fixed":"30bfc2d6a1132a89a5f1c3b96c59cf3e4d076ea3"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-46250.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.7.0"},{"fixed":"5.10.252"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.202"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.165"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.128"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.75"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.14"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-46250.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H"}]}